Inside an ice-cold laboratory in Hobart, where the temperature hovers nearly 20 degrees Celsius below zero, scientists clad in thick puffer jackets commence a groundbreaking task. With gloved hands, they gingerly extract a one-meter cylinder of ice from an insulated box, freshly arrived from Antarctica. This marks the beginning of a monumental scientific endeavor.
“In the freezer lab today, we’re cutting the first samples from the ‘Million Year Ice Core’,” explained Joel Pedro, the lead scientist on the project from the Australian Antarctic Division. “And that’s a big moment for us.”
For nearly a decade, Dr. Pedro and his team from the Australian Antarctic Program have meticulously planned this ambitious project. Known as the “Million Year Ice Core,” the mission aims to retrieve the world’s oldest continuous ice core from deep beneath Antarctica’s frozen expanse.
The Significance of Ice Cores
Ice cores are invaluable to climate scientists because they act as time capsules, preserving a record of Earth’s atmospheric history. “More than any other archive of climate in the past, [ice cores have] a range of information that helps you to understand the changes in the total climate system,” Dr. Pedro noted.
These cores contain tiny air bubbles, trapped over thousands or even millions of years, depending on the ice’s depth. “Those air bubbles are a sample of the atmosphere in the past that was trapped as snow fell and was then compressed into ice,” Dr. Pedro explained. Each bubble serves as a pristine sample of the atmosphere from the time the snow was compacted into ice.
A Grueling Journey to Access Ancient Ice
The ice currently under analysis in Hobart originates from a depth of 150 meters, making it nearly 4,000 years old. While this is a significant milestone, it represents just the beginning of a much larger mission. Over the coming years, the team aims to reach a depth of 3,000 meters, potentially uncovering ice that is up to 2 million years old.
Reaching this point has been a colossal logistical challenge. The drill site, Dome C North, is located 1,200 kilometers from the nearest Australian station in Antarctica and sits 3,000 meters above sea level, where temperatures can plummet below -50 degrees Celsius. Transforming the site into a deep field station required a 10-person team to use six tractors to transport nearly 600 tonnes of equipment across the icy terrain.
“In the Australian program, it’s the biggest traverse that we’ve undertaken,” said Chris Gallagher, the traverse leader from the Australian Antarctic Division.
After enduring multiple blizzards, the team reached Dome C North 18 days after departing from Casey Station. “It’s a very specialized team that has extremely high skills, but also that ability to really get on with each other and care for each other,” Gallagher remarked. “We were like a big family on this trip.”
The Quest for the Oldest Ice
Once the accommodation modules and drill shelter were established, a separate team of scientists flew in to begin drilling and processing the ice core. Chelsea Long, a field assistant, described the extraction of the first section of ice as a momentous occasion. “It was really celebratory when it came out and just finally to see this happening and to touch the ice and measure it, was a real joy,” she said.
For Dr. Pedro, the commencement of the project was a moment to savor after years of hard work and delays caused by the COVID-19 pandemic. “The start to the project was easily the most exciting thing that’s happened in my science career,” he stated. “But at the same time, it’s just the start of the project — we’ve still got 3 kilometers to go.”
Potential Breakthroughs in Climate Science
Currently, the oldest ice core on record dates back nearly 800,000 years. However, a European team known as Beyond EPICA recently extracted ice from a depth of 2,800 meters, which is expected to date back almost 1.2 million years. The Australian team plans to drill more than 200 meters deeper than Beyond EPICA, potentially reaching ice that dates back up to 2 million years.
“If we can get this record − and the modeling suggests [Dome C North] is the best site in Antarctica for recovering [the] oldest ice − then we’ll produce data that will stand for decades as the measurement of Earth’s atmosphere [and] greenhouse gas levels through that period,” Dr. Pedro said. “It’s pretty exciting.”
If successful, the data could help scientists better understand why Earth’s ice ages became much longer about a million years ago. “It remains one of the biggest puzzles, [or] challenges, in ice core science and in climate science to resolve what the cause of that was, and, in particular, what the role of CO2 [carbon dioxide] was in that.”
Data from the “Million Year Ice Core” could also enhance the accuracy of climate change forecasts. The team plans to resume drilling during the 2025/26 summer and expects to reach the 3,000-meter mark by 2028/29.
